Re: [sunset4] Stateless NAT44 vs MAP/4rd

Thanks for your interests in our draft. 

I am not quite sure whether you were asking the mapping between prefixs or IPs. Let me explain both. In our method, mapping between internal prefix and external prefix is 1:1, while mapping between internal IP and external IP is N:1. As shown in Figure 2 and 3, the length of external prefix is longer than the internal prefix. More specifically, the difference between them is the length of port set id. Did this answer the question, or do you have other questions regarding the mapping?

Regards,
Will

> -----Original Message-----
> From: sunset4-bounces@ietf.org [mailto:sunset4-bounces@ietf.org] On
> Behalf Of GangChen
> Sent: Friday, July 20, 2012 2:02 PM
> To: Simon Perreault
> Cc: George, Wes; sunset4@ietf.org; Dan Wing; Will Liu (Shucheng)
> Subject: Re: [sunset4] Stateless NAT44 vs MAP/4rd
> 
> The draft is quite interesting
> One question for clarification
> 
> Is the mapping between Internal Prefix & External Prefix  1:1 or N:1 ?
> 
> BRs
> 
> Gang
> 
> 2012/7/17, Simon Perreault <simon.perreault@viagenie.ca>:
> > On 07/11/2012 12:44 PM, Dan Wing wrote:
> >>> draft-tsou-stateless-nat44-00
> >>
> >> This seems to be a MAP solution.  But differs from MAP in that it uses
> >> an IPv4 network between the subscriber and the ISP's "stateless NAT44"
> >> device, whereas MAP uses an IPv6 network between the subscriber and
> >> the ISP's "MAP border relay" device.
> >
> > I think this is a fair comparison.
> >
> > One advantage of SLNAT44 over MAP is that the necessary changes to the
> > CPE are minimal. For example, a vanilla Linux can do SLNAT44 today.
> >
> > Another advantage of SLNAT44 is simpler provisioning: CPEs don't need to
> > have access to all the "mapping rules" for direct communication to work.
> > In MAP/4rd, a CPE needs to compute the IPv6 address to which the IPv4
> > address it wants to reach is mapped. That's why rules need to be
> > downloaded to the CPE. In SLNAT44, you just send the packet directly to
> > the IPv4 address you want to reach. There is no overlay network, so no
> > rules to be downloaded.
> >
> > Simplicity! :)
> >
> > Simon
> > --
> > DTN made easy, lean, and smart --> http://postellation.viagenie.ca
> > NAT64/DNS64 open-source        --> http://ecdysis.viagenie.ca
> > STUN/TURN server               --> http://numb.viagenie.ca
> >
> >
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